Polycitone B (2) was obtained in four steps from pyrrole dicarboxylic acid 3, including Friedel-Crafts reaction of the corresponding acid chloride with anisole. The conversion of 2 into polycitone A (1) was achieved in two steps via Mitsunobu alkylation of the pyrrolic NH group. The synthesis of polycitone A proceeds in 18% overall yield and offers the possibility of varying the substituents on the pyrrole ring.

Annual plant pulping is faced with serious challenges. Traditional pulping processes with bleaching in chlorine based sequences and without appropriate chemical recovery system cannot be tolerated anymore. Alternative pulping processes with non-conventional chemicals, such as organic solvents, e.g., monoethanolamine (MEA), might be suited for an environmentally sound process with a closed mill system. Thus, pulping of wheat straw with MEA as the main delignifying agent was investigated in comparison to soda and soda/AQ pulps as references. The main focus was placed on reduction of the cooking temperature in order to avoid heat-induced MEA degradation. The temperature was reduced stepwise from 165°C to 130°C. At 150°C, a sufficient delignification was achieved. MEA was partly substituted by water and the resulting decrease of the delignification rate could be compensated by addition of anthraquinone (AQ). After optimization of the process, a pulp with a kappa number of 17 was obtained at a total yield of 56% based on o.d. straw. This pulp was selected for bleaching. Both, O/Q/OP/DQ/P (“ECF light”) and O/Q/OP/ZQ/P (TCFZ) bleaching were applied. NaOH was substituted by MEA as alkali source in the oxygen delignification stage. Up to 50% delignification rate was achieved under these moderate conditions. In the ECF light bleaching sequence, a brightness of 80% ISO was reached at a kappa number level below 3. In TCFZ bleaching, an even somewhat higher brightness was achieved at a kappa number level below 1. A yield of fully bleached screened pulp of around 50% (based on o.d. straw) was obtained. The strength properties of the MEA pulp were improved after bleaching. ECF bleaching resulted in slightly better pulp strengths than the TCFZ alternative. MEA forms in combination with water and AQ a very selective pulping system providing effective delignification and maintaining extremely high yields. MEA/water/AQ pulping should be regarded as a serious, environmentally friendly alternative to soda or soda/AQ pulping to produce high-quality pulp from wheat straw.

Oxidative two-step, one-pot cyclizations of arylpyruvic acids or pyruvates in the presence of ammonia lead to the symmetric indoles (II), (IV) or (VI). Unsymmetrically substituted indoles such as (X) or (XIII) are obtained by reaction of arylpyruvic acids or pyruvates with bromopyruvates. Compound (XIII) is converted into the trimethyl ether (XVI) of the antibiotic lukianol A. -(HINZE, C.; KREIPL, A.; TERPIN, A.; STEGLICH*, W.; Synthesis 2007, 4, 608-612; Fachbereich Chem.,

For Abstract see ChemInform Abstract in Full Text.

The gas-phase epoxidation of 2-butene (trans or cis) has been conducted in a flow-through reactor at a pressure of 0.5 bar and a temperature of 325 °C using a N2/O2 mixture as the carrier gas. The primary oxidizing agent in the feed gas is ozone. Selectivity to epoxide (trans- and cis-epoxide in total) of about 90% is observed. Investigations using mixtures of trans-2-butene with 1-butene or n-butane revealed a clearly preferred reaction of trans-2-butene. Kinetic analysis of the overall process yielded ratios for the corresponding rate coefficients of k(trans-2-butene)/k(1-butene) = 5.4−7.2 and k(trans-2-butene)/k(n-butane) ∼ 67. A few experiments showed a similar behavior for cis-2-butene. Using raffinate 2 (1-butene, 2-butene, n-butane, and iso-butane) as the feedstock for epoxidation, a selective production of 2-butene oxide (trans/cis mixture) is feasible. Additions of methane (1.7−12.5 vol %), H2O vapor (1.7−4.2 vol %), or CO2 (1.7−25 vol %) in the carrier gas do not influence the epoxidation reaction.